基于血红蛋白/硒化镉量子点多层膜的H2O2生物传感器

合成了水溶性硒化镉(CdSe)量子点,利用组装技术和静电吸附作用,将带正电荷的血红蛋白(Hb)和带负电荷的CdSe量子点层层组装到壳聚糖(chit)修饰的玻碳电极(GCE)表面,构建基于{Hb/CdSe}n多层膜的无电子媒介体的电流型生物传感器({Hb/CdSe}3/chit/GCE).运用紫外-可见吸收光谱、电致化学发光、交流阻抗和循环伏安技术来表征修饰膜,并研究传感器的作用机理、性能及分析应用.结果表明:与量子点薄膜法及量子点/血红蛋白复合物法等固载血红蛋白的其他方法相比,层层组装法能显著提高血红蛋白的固定量,保持血红蛋白的生物活性,增强传感器的灵敏度和稳定性.传感器检测H2O2的线性范围为4.0×10-8～4.8×10-6 mol·L-1(r=0.999 1),检测限为2.0×10-8mol·L-l.多层膜的电致化学发光研究,表明修饰电极有望用于电致化学发光传感器的制备.

H2O2 Sensor Based on Hemoglobin/CdSe Quantum Dots Multilayer Films

Water soluble CdSe quantum dots(QDs) have been synthesized. Hemoglobin(Hb) and CdSe QDs could be immobilized on the surface of chitosan modified glassy carbon electrode by layer-by-layer self-assembly method and electrostatic interactions. Then the third-generation amperometric biosensors({Hb/CdSe}₃/chit/GCE) based on {CdSe/Hb}_n multilayers were constructed, and the direct electrochemistry of Hb was obtained from the multilayer films. The obtained films were characterized by UV-Visible spectroscopy(UV-Vis), electrogenerated chemiluminescence(ECL), electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV). The mechanism, properties, and analytical application of the sensor were also studied. The experimental results show that Hb in the multilayer films keeps its native configuration and bioactivity. CdSe QDs integrated in the multilayer films not only improve the electron-transfer between the Hb and GCE, increase the catalytical activity of Hb, but also prevent the leakage of Hb. The biosensors based on the multilayer films have good stability and electrocatalysis to H₂O₂, and shows a linear response to the concentration of H₂O₂ ranging from 4.0×10^-8 to 4.8×10^-6 mol·L^-1 with a detection limit of 2.0×10^-8 mol·L^-1.